|Cracks in Installed Reinforced Concrete Pipe
Resource # 02-712
“Some engineers insist that a crack in a concrete pipe in excess of 0.01-inch represents a failure or partial failure situation. Such a conclusion is utterly ridiculous and represents a disservice, not only to the concrete pipe industry, but taxpayers as well.” This quote from Professor M.G. Spangler, a well-respected authority and early pioneer in the design of concrete pipe, should be taken into consideration when designing, installing, inspecting, or funding a project using reinforced concrete pipe, (RCP). All parties involved should be aware of the insignificance of a 0.01-inch crack.
|Practical Accuracy of Crack Measurement
Resource # e-014
Pipe industry professionals have observed the use of precision measurement technology without a full appreciation of the limitations of the equipment and the human factors involved. This results in inaccurate crack measurements. In general, pipe utility contractors have come to accept and support final inspection results. However, inconsistency and unreliability of field measurements erodes confidence in the inspection process. This, in turn, threatens the future of final inspection and crack measurements approximating crack widths when assessing pipe conditions. For this reason, the pipe inspection and construction engineering communities must fully understand the practical accuracy of using precision crack measurement technology.
|Effects of Cracks in Reinforced Concrete Sanitary Sewer Pipe
A Sanitary Sewer line constructed for the Brazos River Authority contained both 30 and 42-inch diameter reinforced concrete pipe with a 2-inch cover over the inner cage reinforcing to provide sacrificial concrete. After installation, inspection reveal a longitudinal crack had developed at the inside crown of both size pipe. The study objectives are as follows:
· Determine the depth of the cracks
· Develop load strain and load deflection information during three-edge-bearing tests of a representative pipe section up to the formation of both hairline and 0.01-in cracks
· Study the effects of an acid environment on the concrete and reinforcement exposed by cracks
· Evaluate Autogenous healing
|Effects of Cracks in Reinforced Concrete Culvert Pipe
Over the years, there have been numerous discussions as to the degree of interior cracking that can be tolerated in relation to the integrity and life expectancy of reinforced concrete pipe. Due to limited documentation on this problem, the Las Angeles County Flood Control District requested a study of the relationship of the 0.01-inch crack width to corrosion induced failure.